Device for regulating the compression-space of internal-combustion engines.



w. SCHMIDT. 1f bgvlcf roREeuLATmG THE coMPnEssloN sPAcE Ulf-'INTERNAL coMBusnoN ENGINES..

' h APPLICATION FILED NOV. 2. 1915l 1,167,023, 'I Patenfd Jan. 4, 1916.

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UNITED STATES PATENT oEEioE.

I WILHELM SCHMIDT, 0F WERNIGERODE, GERMANY.

DEVICE FOR. REGULATING THE COMPRESSION-SPACE 0F INTERNAL-COMBUSTION ENGINES.

Application led November 2, 1915. Serial No. 59,266.

To all/whom t may concern Be it known that I, WILHELM SCHMIDT, a citizen of the German Empire, residing at Vernigerode, Germany, have invented a certain new and useful Improvement in Devices for Regulating the Compression- Space offilled with liquid. This known arrangement l has been practically unsuccessful by reason of its complexity and vunreliabilityv in operation.

The object of the present invention is to .do away with the disadvantages attendant upon the use of known structures above referred to and this object is attained by' a novel arrangement and combination of parts as will hereinafter be described.

My invention will be better understood by referring to the accompanying drawing which represents a central longitudinal section -through a preferred embodiment thereof. f

My invention resides essentially in a channel which contains a non-return valve and v connects the liquid filled chamber behind the piston or into which the piston extends with a receptacle containing a supply of liquid, andfanother channel contalmng an over-pressure valve which opens away from said chamber.

Referring to the drawings, a is the working cylinder' of an internal combustlon engin'e, b is the working piston, and c is the compression space,l said space being closed,

. oppositel to the piston b,"by an additional regulating piston d which may be displaced in an auxiliary cylinder e whichiorms an extension of cylinder c. Cylinder e is bolted at its rear end to a casing lc, anges c and 7c being provided for this purpose; flange fc', at its inner edge, is formed' as a'rlng'h which serves as-an vabutment for the piston d so as Specification of Letters Patent.

Patented Jan. 4, 191e.

to limit the rearward movement of said piston, z'. e., its movement away from the cylin, der a and the piston d so as to make the compression space largr. This compression space 1s a maximum when the piston d is incontact with the abutment ring z..

Casing forms a control cylinder for another control piston z' which is connected with pistonol by piston rod z". rlhe space between the pistons g and i is connected by ports f with the outer air. Thecontrol cylinder k is, within the space just mentioned, provided with an internal angular projection lf2 forming with the cylinder wall an annular groove Ica from which a drip pipe 7c* extends tothe outside of the cylinder. vThe control cylinder lc is closed at its upper end by a cover n, and the chamber w between 'this cover and the piston z' is filled with a liquid, preferably an oil.

A helix 0 is provided in chamber w. between cover n and piston i so as to exert a constant pressure upon said'piston, and the piston d connected therewith, so as to de' crease the compression space to a minimum, z'. e., to that size at which the downwardly extended peripheral rim of piston is located at the bottom of groove 7c3. The cover n, has two channels p and r, the former containing a non-return valve g, and the latter an overpressure valve s; a helix t tends to hold the ball of this over-pressure valve 'upon its seat. i

Channel p is connected with a receptacle p containing a liquid p2, and channel r may be connected with an overflow receptacle (not shown), similar to receptacle p', adapted to receive any liquid forced out of the chamber fw; or channel r, may, if desired, be connected with the receptacle p so that any liquid forced out of chamber w will be returned to the supplyfrom which it came.

When piston z is moved in the direction of the piston g, the oil or other liquid will How through channel p into the chamber fw, aroundthe ball of the non-return valve g, but if the piston i is moved in the other direction, the o il or other. liquid will pass through the channelr, around' the ball of the over-pressure valve s, into the overflow receptacle. The helix t of the over-pressure A `valve s may be regulated by a threaded screw u.

The operation of my invention is as folt lows: Let the engine be assumed to be under full and constant loadand the explosion'to have just taken place; then the piston d will be in itsv highest position and in contact with ring of angek. Compression space c is now the maximum, its size having been so determined that the most favorable nal compression pressure, as well as the most favorable explosion pressure, is obtained with respect to that quantity of combustible mixturel which corresponds to that full load.

5@ During the explosion, and during the immediately following expansion, pistoncl remains .l

in the just stated position, because the pressure then existing within the working cylinder is greater than the 'tension of helix o. As soon, however, as the exhaust period commences, the tension of helix o becomes greater than' the .pressure within the working cylinder and this helix then tends (through control piston z' and piston rod z" to move 2c the piston ci 0E its seat. But since the overmovement of theregulatingpiston ceasesV when the compression period commences and, at the next explosion the piston olis again moved against, and pressed upon the Seat-or abutment L. During the return movement of piston d, liquid is forcedV out of the chamber fw through channel r by means of piston z'. This to and fro play is accurately 40 the same during every cycle. Tn a four cycle engine, for instance, there are four strokes or movements of the piston d for every cycle, each of the strokesbeing very short, however, if the load of the engine remains the same. The length of the strokes is influenced to a certain extent bythe R; l?. M. of the en,-

gine shaft, this length tending to decrease with an increase of R. lf. M. and to increase with a decrease of R. l). M.; with a sulicient h number of R. P.' M. the movements of the piston a? may be practically negligible. lf, now, the load of the motor be decreased, .for example, to about one-half of its former magnitude, thenv only about half of the E56 former quantity of explosive mixture is needed, and since the piston d is, at first, still in its highest position', i. e., at or near to the abutment ring h, the compression space will be too large with respect to the reduced load.

oo The explosion pressure will become too small, therefore, to act upon piston v1 so as to force s liquid out of chamber fw through .channel r. Tn other words, pistons a' and Z Will, at the first explosion stroke after reducing load, remain substantially in theposition they as- 4spondingly change, being closer to the workthen the explosion pressure will be greater sumed at 'the last exhaust stroke of piston At the next exhaust stroke and suction stroke the pistonsz' and Z will sink farther, t'. e., they will be .displaced farther toward piston b by means of helix o, a'nd the amount of this displacement will be greater than it was during the state previously described. The pistons and e, are now displaced, not only by the helix o, but also by the over-pressure which now exists in chamber@ in comparison with the pressure within compression space c, since owing to the throttling of the combustible mixture upon its Way to cylinder a, a certain partial vacuum has been produced in said space c. The diminution of the compression space is still quite small, and the pressure arising at the next explosion will not be suliicient to move the pistons back to their former position. Hence, at the next exhaust and suction strokes, the-pistons will sink still farther and this step-by-step movement, in the direction of the working cylinder, `will continue during the successive cycles until the compression space has been so far reducedthat the explosion pressure eo will again be able to remove the piston Z to that position which it has .occupied at the commencement of the just ,preceding suction stroke. This restablished oscillatory movement of the piston d will continue as long as the now existing load of the engine remains unchanged, but when the load is again A changed, the position of the limits between which the piston Z will oscillate will correing piston d or morerrem'ote therefrom, according as the load of the engine may have been still further decreased, or increased. Tf the load be supposed to have increased,

than. it 'was before and the -piston ai will be correspondingly raised, by steps, as before described, until the compression space has attained a size which corresponds to the new condition .of constant load. lt may be seen, therefore, that the chan-ges or variations in size of the'compre'ssion space take place yautomatically, always corresponding to the load, to the appropriate quantity of the explosive mixture, and to the explosion pressure orI final explosion pressure. The magnitude of this pressure may be determined or regulated by means of screw u and`helix t, and this may be done while the engine is running. @ther means may be employed for changing the pressure of the helix t if desired; furthermore, the over-pressure valve u may be of any other suitable construction, asmay also other details.

Having described my invention l claim: 1. ln an internal combustion engine, in combination with the working cylinder, a regulating piston which constitutes a wall thereof at the compression space, an auxiliary cylinder opening into the compression 13o Vnels being connected with a receptacle which contains a liquid and said channell itself containing a non-return valve, and an over-pressure valve in the other channel.

2. In an internal combustion engine, in combination with the working cylinder, a regulating piston which constitutes a Wall thereof at the colnpression spacean auxiliary cylinder opening into the compression space land containing the regulating piston, means for limiting the movement of the regulating piston within its cylinder'. Aa spring acting upon the regulating-piston tending to move said piston toward the working cylinder, a pair of channels opening from the end of the vcylinder space behind the regulating piston, one of said channels being connected with a receptacle which contains a liquid and said channel it! self containing a non-return valve, and an over-pressure valve in the other channel. l

3. In an internal combustion engine, in combination With the working cylindeig'a regulating piston which constitutes a' Wall thereof at the compression space, an auXiL iary cylinder opening into the compression space and containing the re ulating piston, a control cylinder, a contro piston Within the control cylinder, means connecting the regulatingv and control pistons so that they move simultaneously, a spring acting upon the controlpiston so that the regulating piston tends to move toward the working cylinder, a pair of channelsv opening from the end of the control cylinder behind the control piston, a non-return valve in one of said channels, an over-pressure valve in the other channeh'and a receptacle containing liquid into which the channelcontaining the non-return valve opens.

4.A In an internal combustion engine, in combination with the working cylinder,y a regulating piston lwhich constitutes a wall thereof at the compression space, an auxiliary c vlindeil opening into the compression space and containing the regulating piston. a control cylinder, a control piston .Within the control cylinder, means connecting the regulating and control pistons so that they move simultaneously, a spring acting upon the control piston so that the regulating piston tends to move toward the working cylinder, an opening from` the .atmosphere to the rear surface of the regulating piston, a pair of channels opening from the end of the control cylinder behind the control piston, a non-return valve in one of said channels, van over-pressure valve in the other channel, and a receptacle containing liquid y into which the channel containing the nonreturn valve opens, l l

In testimony whereofI have hereunto set my hand in the presence of tw'o subscribing Witnesses.v

y WILHELM SCHMIDT.

lVitnesses i yMILO'A. JEWETT, v J. C.-MEN.\LLY. Y 

